Table of Contents

Linked Birth/Infant Death Data Series

Investigator(s): National Center for Health Statistics

These data are provided by the United States Department of
Health and Human Services, National Center for Health Statistics to be used in
determining infant mortality rates. Each data collection consists of two types
of files. The first file type provides linked records of live births and deaths
of children born in the United States (to residents and nonresidents). This file
is called the Numerator File. The second file type consists of live births in the
United States and is referred to as the Denominator File. Beginning in 1989, a
number of items were added to the U.S. Standard Certificate of Birth. These
changes and/or additions led to the redesign of the linked file record layout for
this series and to other changes in the linked file. In addition, variables from
the Numerator File were added to the Denominator File to facilitate processing,
and from 1989 on this file is called the Denominator-Plus File. A third file
type was added in 1989 called the Unlinked File, which consists of infant death
records that could not be linked to their corresponding birth records. In 1995,
data for Puerto Rico, the Virgin Islands, and Guam were included, and there was
a change in format of the linked files, which were released in two different
formats, period data and birth cohort data.